Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/0051—Tabular grain emulsions

Definitions

• This invention relates to a silver halide emulsion useful in the photographic field and to a silver halide color photographic light sensitive material applied with the above-mentioned emulsion and, particularly, to the silver halide emulsion remarkably improved in image-sharpness and pressure characteristics and to the silver halide color photographic light sensitive material applied with the above-mentioned emulsion, which is excellent in image-sharpness, pressure, color reproduction characteristics and gradation.
• JP OPI Publication U.S. Patent No. 4,439,520 and Japanese Patent Publication Open to Public Inspection (hereinafter referred to as JP OPI Publication) Nos. 62-99751(1987) and 62-115435(1987) disclose the multilayered color photographic light sensitive materials having a high speed and an excellent dye-image sharpness in which the high speed layer thereof contains a tabular-grained silver halide emulsion having a grain thickness of less then 0.3 ⁇ m and an aspect ratio of not less than 8 : 1.
• JP OPI Publication Nos. 57-93344(1982), 54-145135(1979) and 57-151944(1982) disclose the techniques for improving image-sharpness by making use of the diffusible DIR.
• the techniques of the tabular-shaped grains may be classified into those for improving an image-sharpness upon utilizing an optical effect, and the techniques of the DIR compounds may be classified into those for improving an image-sharpness upon utilizing a development effect.
• a light scattering produced of silver halide grains will seriously affect an image-sharpness and, as pointed out in each of the foregoing patent publications, an image-sharpness is remarkably improved when the silver halide grains are each tabular-shaped and have a thickness of less than 3 ⁇ m.
• JP OPI Publication Nos. 58-113926(1983), 58-113927(1983) and 58-113926(1983) disclose each the emulsion grains having an aspect ratio of not less than 8.
• an 'aspect ratio' means a ratio of the thickness of a tabular-shaped silver halide grain to the diameter thereof.
• the term, 'the diameter of a grain' means the diameter of a circle having the same area as the projective area of the grain when an emulsion is observed through a microscope or an electron microscope.
• the term, a 'grain thickness' means the distance between the two parallel surfaces constituting a tabular-shaped silver halide grain.
• tabular-shaped silver halide grains are characterized in hardly monodispersing themselves as compared to any nontabular-shaped silver halide grains (which are regularly crystallized).
• tabular-shaped silver halide grains which are regularly crystallized.
• JP OPI Publication Nos. 52-153428(1977), 55-142329(1980), 61-112142(1986) and 51-39027(1976) and French Patent No. 253,406 disclose each the techniques for monodispersing tabular-shaped silver halide grains.
• the silver halide grains used therein have a low aspect ratio of less than 3 or they are the mixture of hexagonal and triangular tabular grains. Therefore, they are still not satisfactory for the monodisperse type tabular-shaped grains.
• the tabular-shaped grains uniform in both configuration and grain-size the monodisperse type tabular-shaped grains mainly having a hexagonal configuration have been disclosed in JP OPI Publication Nos. 63-151618(1988, 1-213637(1989) and 2-838(1990).
• the tabular-shaped silver halide grains such as those mentioned above are seriously poor in pressure characteristics and it has been difficult to improve any image-sharpness without deteriorating the pressure characteristics in any conventional techniques.
• the term, 'pressure characteristics' has the two meanings; one meaning is that an unexposed portion is developed, that is so-called a pressure fog and the other meaning is that a photosensitive speed is lowered when making an exposure, that is so-called a pressure desensitization, each when a pressure is applied to a silver halide photographic light sensitive material. If the above-mentioned characteristics are poor, the silver halide photographic light sensitive material will have a serious defect.
• silver chloride, silver chlorobromide, silver chloroiodobromide, silver iodide or silver iodobromide may selectively be used so as to meet the purposes and applications of light sensitive materials.
• silver iodobromide may often be used in color photographic films for general use.
• the distribution of the grain compositions inside silver halide grains is optimized for controlling the gradations, color reproducibility and photosensitive speeds, as well as for controlling the pressure characteristics thereof. Therefore, when the color reproducibility and gradations are improved, there may often raise such an antinomic problem that the pressure characteristics may be deteriorated.
• a silver halide when a silver halide has a higher iodine content, the silver halide will be sensitized higher. However, the light absorption wavelength region inhering in silver halide will affect the long-wavelength side and color reproducibility. Therefore, a high image-quality color film can be improved in color reproducibility by making use of silver iodobromide having a low iodine content.
• silver halide is made to have a low iodine content, however, there raises such a problem that the developability (that is, the developing speed) of silver halide grains may be increased so that the gradation may be hardened.
• tabular-shaped silver halide grains will have a developing speed higher than those of the other-shaped grains even if the halogen composition thereof are the same with each other. In this case, the above-mentioned hard gradation problem may, therefore, become remarkable.
• silver halide grains are to have a higher monodispersibility.
• the gradation thereof is hardened.
• tabular-shaped silver halide grains having a low iodine content for the purposes of improving color reproducibility and image-sharpness, it cannot prepare nothing but a strikingly hard light sensitive material.
• the above-mentioned gradation problem is essential and, it has, therefore, been demanded to provide an emulsion excellent in color reproduction characteristics, that is, an emulsion low in iodine content, excellent in both image-sharpness and pressure characteristics, but without spoiling the gradation thereof.
• Another object of the invention is to provide a silver halide emulsion without spoiling any gradation, but excellent in image-sharpness, color reproducibility and pressure characteristics and, at the same time, to provide a silver halide photographic light sensitive material applied with the above-mentioned emulsion.
• the invention can be achieved with a silver halide emulsion characterized in satisfying the following requirements:
• the invention can also be achieved with a silver halide photographic light sensitive material characterized in the following requirements:
• the light sensitive material is to comprise a support bearing thereon at least one of light sensitive silver halide emulsion layers and at least one of non-light sensitive hydrophilic colloidal layers; At least either one of the light sensitive silver halide emulsion layers is to contain the silver halide emulsion claimed in claim 1; and
• the total dried layer thickness thereof is to be not thicker than 2.0 ⁇ m.
• the invention can further be achieved with a silver halide photographic light sensitive material claimed in claim 2, which is characterized in the following requirements:
• the light sensitive material is to comprise a support bearing thereon at least one each of red-sensitive silver halide emulsion layers containing each a cyan coupler, green-sensitive silver halide emulsion layers containing each a magenta coupler and blue-sensitive silver halide emulsion layers containing each a yellow coupler; At least either one of the green-sensitive silver halide emulsion layers and/or the blue-sensitive silver halide emulsion layers is to contain the silver halide emulsion claimed in claim 1.
• an 'aspect ratio' herein means the diameter/thickness ratio of a subject grain
• a 'diameter of a silver halide grain' herein means the diameter of a circle having the same area with the projective area of a subject grain
• a 'grain thickness' herein means a distance between two parallel faces constituting a subject tabular-shaped silver halide grain.
• the expression, 'a hexagonal tabular-shaped grain' herein means that a subject grain has a hexagonal (111) face and a maximum adjacent side ratio within the range of 1.0 to 2.0.
• the term, 'a maximum adjacent side ratio' herein means a ratio of the length of the shortest side of a hexagon to the length of the longest side thereof.
• the hexagonal tabular-shaped grains of the invention may also have rounded corners to some extent, provided, the maximum adjacent side ratio thereof is to be within the range of 1.0 to 2.0.
• the length of a hexagonal side is to be expressed by the distance between the two points intersecting a line extended from the straight portion of a subject side and each of the lines extended from the straight portions of the adjacent sides each other.
• each of the sides thereof substantially comprises a straight line having a length of, desirably, not shorter than one half of the side length and, preferably, not shorter than four-fifths of the side length.
• an adjacent side ratio is preferable to be within the range of 1.0 to 1.5.
• the silver halide emulsions of the invention are generally comprised of a dispersion medium and silver halide grains.
• the grains are each shaped in a hexagon having an adjacent side ratio within the range of 1.0 to 2.0. And, the grains are occupied by tabular-shaped silver halide grains each having two parallel twinned-crystal faces.
• the hexagonal tabular-shaped grains stated in the invention are characterized in having a plurality of (e.g., a couple of) parallel twinned-crystal faces. This fact can be confirmed by observing the cross section of the thin layer cut piece of an emulsion-coated film at a low temperature (i.e., at a liquid nitrogen temperature) through a transmission type electron microscope.
• the term, 'the variation coefficient of grain sizes', stated in the invention, herein means the degrees of a grain size scattering, and it is expressed by a percentage obtained when the standard deviation of the projective areas (converted into the circular diameter) of hexagonal tabular-shaped grains of the invention having a maximum adjacent side ratio within the range of 1.0 to 2.0 is divided by the average grain size.
• the term, 'the variation coefficient of grain thickness' means the degrees of a grain thickness scattering, and it is expressed by a percentage obtained when the standard deviation of the thickness of hexagonal tabular-shaped grains of the invention having a maximum adjacent side ratio within the range of 1.0 to 2.0 is divided by the average thickness.
• the silver halide grains of the invention are comprised of tabular-shaped grains having an aspect ratio within the range of 3.0 to 7.0. It is preferred that the tabular-shaped grains are to have an aspect ratio within the range of 3.0 to 7.0 in at least 70% of the whole projective area.
• the aspect ratio thereof is to be within the range of 3.0 to 4.9, desirably, in at least 50% of the whole projective area and, preferably, in at least 70% of the whole projective area.
• the aspect ratio is too high, pressure characteristics (such as a pressure desensitization and a pressure fog production) will be deteriorated, because the maximum moment is increasingly applied to silver halide grains when a pressure is applied to a light sensitive material.
• the aspect ratio is too low, an image-sharpness will undesirably be deteriorated by a light scattering, because grains are thickened to shorten the projective diameter so as to become closer to the length scattering visible rays of light.
• the above-mentioned aspect ratio has an optimum value from the viewpoints of pressure characteristics and image-sharpness. It is, therefore, the matter of course that the proportions of the grains out of the desirable aspect ratio range are preferred to be the less, the better in the distribution of silver halide grains.
• At least 70% of the whole projective area of the silver halide grains contained in an emulsion is to be occupied by the silver halide grains of the invention each bearing even numbers of the twinned crystal faces parallel to the principal face formed in a hexagon having a maximum adjacent side ratio within the range of 2.0 to 1.0; and at least 90% of the whole projective area is preferably occupied by the hexagonal tabular-shaped silver halide grains such as those mentioned above.
• At least 70% of the whole projective area is occupied by hexagonal tabular-shaped grains having a maximum adjacent side ratio within the range of 0.1 to 1.5 and it is further preferable that at least 90% of the whole projective area is occupied by hexagonal tabular-shaped grains having a maximum adjacent side ratio within the range of 0.1 to 1.5. If the percentage of the hexagonal tabular-shaped grains is relatively low, it makes higher the percentage of the mixture of various other-shaped silver halide grains such as those having regular-crystals, triangular twinned crystals and various multiple twinned crystals.
• the grains are chemically sensitized on different levels according to the configurations of the grains, because the chemical sensitization is seriously affected by the configurations, surface indexes, compositions and defects each of silver halide grains. It is, therefore, not only unable to satisfy the optimum chemical sensitization requirements because of the relation between a sensitivity and a fog production, but also unable to make the pressure characteristics satisfactory as the whole, because the grains worse in pressure fog production and excessive in chemical ripening are mixed with the grains worse in pressure desensitization and insufficient in chemical ripening.
• the average silver iodide content of silver iodobromide is desirably not more than 10 mol%, more desirably not more than 8 mol% and preferably not more than 6 mol%.
• pure silver bromide having a silver iodide content of less than 0.5 mol% is preferably used.
• those having a slight silver iodide content is desirably used.
• the optimum silver iodide content is within the range of 0.1 to 6 mol%, desirably 0.5 to 4 mol% and preferably 1 to 3.5 mol%.
• the average silver iodide content is preferably within the above-mentioned range.
• the silver iodide contents of individual silver halide grains of an emulsion are preferable to be uniform among the grains, because a chemical sensitization is affected by the silver iodide content thereof as well as by the aforementioned grain configurations.
• the silver iodide contents of individual grains can be measured by making use of an XMA (standing for an X-ray microanalyzer).
• such a relative standard deviation is desirably not more than 20% and preferably not more than 15%, from the viewpoint of pressure characteristics.
• the grain sizes thereof are desirably not smaller than 0.4 ⁇ m, more desirably within the range of 0.5 to 3.0 ⁇ m and preferably within the range of 0.5 to 1.7 ⁇ m.
• the average grain thickness thereof is within the range of desirably 0.05 to 0.3 Mm, more desirably 0.05 to 0.25 ⁇ m and preferably 0.05 to 0.20 ⁇ m.
• the grain sizes and grain thicknesses thereof can be optimized so as to make the sensitivity, image-sharpness and pressure characteristics most excellent.
• the optimum grain size and the optimum grain thickness may be varied by other factors exerting an influence on sensitivity, image-sharpness and pressure characteristics, (such as the thicknesses of hydrophilic colloidal layers, layer hardening degrees, chemical ripening conditions, the amounts and kinds of DIR compounds used, the ISO speeds and silver-coating weights of a subject light sensitive material) which constitute a light sensitive material.
• the image-sharpness is more deteriorated when an average grain size and average grain thickness are more closer to a scattering length (within the range of 0.3 ⁇ m to 0.5 ⁇ m).
• the thicker the grain thickness is the better the pressure characteristics are.
• the larger the grain size is the more the sensitivity is increased, but the graininess is deteriorated. It is, therefore, preferable as same as in the cases of the conventional emulsions to select the minimum grain size so as to provide a necessary sensitivity.
• a grain size scattering is to be as small as possible, that is, a monodispersibility is to be as higher as possible.
• the emulsions of the invention have a problem that the gradation is hardened, because the emulsions of the invention comprise each tabular-shaped grains having a higher developing rate and low iodine-containing grains, and the gradation is accelerated to be hardened by the grain sizes are monodispersed, so that the emulsions cannot be used.
• an optimum grain size distribution is selected out of the range within which the pressure characteristics and gradation can both be compatible.
• the optimum grain size variation coefficient is to be within the range of 21 to 29% and the hexagonal tabular-shaped grains of the invention have the variation coefficient within the above-specified range that is preferably between 21% to 26%.
• the variation coefficient is too large, a chemical sensitization aptitude becomes unsatisfactory and the pressure characteristics are deteriorated by the above-mentioned presumptive reasons.
• the variation coefficient is less than 21%, the gradation is unfavorably hardened, but the pressure characteristics become better. From this fact, an antinomic requirement is raised for the variation coefficient.
• the present inventors have discovered through their studies that the pressure characteristics are improved as mentioned above and the excellent pressure characteristics can be displayed up to the region where the grain size variation coefficient is relatively larger. In other words, an excellent gradation can be displayed without spoiling any pressure characteristics within the variation coefficient range of 21 to 29%.
• the optimum thickness of the silver halide grains applicable to the invention is selected so as to balance the pressure characteristics with the image-sharpness. Even when an average grain thickness is the same, the smaller the grain thickness scattering is, the better. In other words, it may be considered that, even if the grains have a preferable average grain thickness from the viewpoints of pressure characteristics and image-sharpness, some parts of the too thick grains produce a light scattering and an image-sharpness deterioration and some parts of too thin grains produce a pressure fog and a pressure desensitization, so that these grains produce the defects of an emulsion.
• the grain thickness distribution that is the grain thickness variation coefficient, is expressed by a percentage of the standard deviation of individual grain thickness to the average thickness thereof. On the hexagonal tabular-shaped grains of the invention, the thickness variation coefficient thereof is to be not more than 20% and preferably not more than 15%.
• the emulsions of the invention are useful when they are used in various types of light sensitive materials.
• the emulsions of the invention are remarkably effective particularly when they are used in a silver halide photographic light sensitive material comprising a support bearing thereon at least one of light-sensitive silver halide emulsion layers and at least one of non-light sensitive hydrophilic colloidal layers and containing the silver halide emulsion of the invention in at least one of the light-sensitive silver halide emulsion layers and, further, having not thicker than 2.0 ⁇ m of the total dried thickness of the whole non-light sensitive hydrophilic colloidal layer apart from the support farther than the light sensitive silver halide emulsion layer apart farthest from the support.
• the hydrophilic colloidal layer is made present as the outermost layer of the light sensitive material (hereinafter referred to as a protective layer) so as to play a role of protecting the silver halide emulsion layers from both of a pressure desensitization and a pressure fog production, and because the thinner the protective layer is in a light sensitive material, the worse the pressure characteristics are and the pressure characteristics of an emulsion may remarkably reflect on the characteristics of the light sensitive material.
• the protective layer of a light sensitive material When the protective layer of a light sensitive material is made thicker, the pressure characteristics are improved. However, the image-sharpness is deteriorated in the silver halide emulsion layers coated underneath the protective layer (i.e., close to the support side). Therefore, a thinner protective layer is preferable for making higher the image-quality of a light sensitive material.
• the silver halide emulsions of the invention excellent in pressure characteristics are useful because the effects thereof can be displayed particularly when they are used in a light sensitive material having such a thinner protective layer as mentioned above and an excellent image-sharpness.
• the image-sharpness of a light sensitive material having a thin protective layer are not so much deteriorated by the presence of a protective layer and, therefore, the light scattering of silver halide grains becomes dominant. Also regarding the image-sharpness, the effects of the tabular-shaped silver halide grains of the invention can remarkably be displayed particularly in a light sensitive material having such a thin protective layer as mentioned above..
• the thickness of a protective layer means the total dried layer thicknesses of the whole non-light sensitive hydrophilic colloidal layer apart from a support farther than the silver halide emulsion layer apart farthest from the support.
• the thickness thereof can be measured by cutting a light sensitive material into pieces by making use of a microtome and then by measuring the cut pieces through an optical or electron microscope.
• the pressure characteristic and image-sharpness effects of the emulsions of the invention can be remarkably displayed in a light sensitive material provided with a thin protective layer having a layer thickness of not more than 2.0 ⁇ m and particularly not more than 1.5 ⁇ m.
• the effects of the invention can be displayed in a light sensitive material provided with the above-mentioned thin protective layer and the invention is useful in a variety of light sensitive materials such as a monochromatic light sensitive material, a color reversal film and a color negative film and, the invention is particularly useful in a multilayered color light sensitive material.
• the tabular-shaped silver halide emulsions of the invention in the green-sensitive and/or blue-sensitive silver halide emulsions of a silver halide color photographic light sensitive material comprising a support bearing thereon at least one each of red-sensitive silver halide emulsion layers containing cyan color developing couplers, green-sensitive silver halide emulsion layers containing magenta color developing couplers and blue-sensitive silver halide emulsion layers containing yellow color developing couplers.
• the above-mentioned usefulness may be presumed because the blue-sensitive and green-sensitive layers are provided relatively far from the support that is provided closer to a protective layer so that the layers are liable to be affected by a pressure and the image-sharpness is liable to be affected by a light scattering in the silver halide emulsion layer provided closer to the support.
• each of the color-sensitive layers may be comprised of a single silver halide emulsion layer or may be comprised of a plurality of layers each having the different speeds.
• the layer containing the silver halide emulsion of the invention is comprised of a plurality of layers, the effects can be displayed when at least one of the component layers contains the silver halide emulsion of the invention. It is, however, preferable to contain the silver halide emulsion of the invention in two or more of the component layers.
• the hexagonal tabular-shaped grains may be comprised of any one of silver bromide, silver iodobromide, silver chlorobromide and silver chloroiodobromide and, among them, silver bromide and silver iodobromide are preferably used.
• Silver iodide may preferably be contained in an amount within the foregoing range.
• the crystal structures thereof are allowed to have a uniform structure, the compositions heterogeneous between the inside and the outside or a layered structure. It is also preferable to contain reduction-sensitization silver nuclei in the grains.
• the emulsions may be of the core/shell type.
• the core/shell type emulsion mentioned herein means an emulsion comprising the grains each having at least an inner part (a core) and at least one outer layer (a shell), such as the double layer structured grains given in JP OPI Publication No. 61-148442/1986 and the multilayer structured grains given in JP OPI Publication No. 61-245151/1986.
• the core/shell type emulsions may be comprised of the grains having a high iodine-containing phase, that is, a silver iodobromide or silver chloroiodobromide phase having a silver iodide content of not less than 10 mol%, desirably not less than 20 mol% and preferably not less than 25 mol%.
• a controlled double-jet method is particularly desirable from the viewpoint that a pH and a pAg can readily be controlled.
• iodine ions can usually be supplied either from an aqueous alkaline iodide solution or from the mixture of the above-mentioned aqueous solution and an aqueous solution of other alkali halides.
• Iodine ions may more desirably be supplied in a method in which silver iodide is supplied in the form of a solid as mentioned in JP OPI Publication No. 1-323215/1989.
• the materials for growing the crystals can be supplied in a triple-jet method of making use of an aqueous ammoniacal silver salt or an aqueous solution of a water-soluble silver salt, an aqueous alkaline bromide solution and a suspension containing silver iodide grains.
• the pH and pAg thereof can be controlled in the same manner as in an ordinary controlled double-jet method.
• a high iodine containing phase can effectively and uniformly be formed, and a silver halide emulsion excellent in image-sharpness and pressure characteristics, which is objective of the invention, can effectively be prepared by making combination use of the silver halide emulsion of the invention.
• a variety of the means applicable to the field of the art can be used. For example, it is allowed to use the techniques such as a technique for doping various kinds of heavy metal salts and the complexes thereof into silver halide grains, a desalting technique (for removing dissolved residuals) and a technique for chemical sensitization, a physical ripening or a spectral sensitization.
• the silver halide grains may be of the core/shell types having various structures.
• the silver halide emulsions are also allowed to contain an azole or other various compounds for the purposes of preventing a fog production or stabilizing the photographic characteristics in the courses of carrying out the emulsion preparation steps, preserving the emulsion or processing the development thereof.
• the above-mentioned emulsions are further allowed to contain various kinds of binders such as gelatin as a dispersion medium.
• a gelatin layer hardener When forming an emulsion layer, a gelatin layer hardener may be used.
• a silver halide emulsion is further allowed to contain, besides the above, a variety of well-known surfactants with the various purposes of serving as a coating aid or of preventing an staticity, improving a slidability, making an dispersive emulsification, preventing an adhesion and improving photographic characteristics (such as a development acceleration, a layer hardening and a sensitization).
• the couplers are desirable to have a hydrophobic group that is so-called a ballast group in the molecules thereof so that the couplers can be non-diffusible.
• the couplers may have either a 4-equivalency or a 2-equivalency to a silver ion.
• Each of the couplers is also allowed to contain a colored coupler having a color correction effect or a coupler capable of releasing a development inhibitor (that is so-called a DIR coupler) as a development is being progressed. Further, the couplers may also be those producing a colorless product upon coupling reaction.
• any well-known closed-chain ketomethylene type couplers can be used.
• a benzoyl acetanilide type and pivaloyl acetanilide type compounds may advantageously be used.
• the typical examples of the yellow color-developing couplers applicable thereto include those given in U.S. Patent Nos. 2,875,057, 3,265,506, 3,408,194, 3,551,155, 3,582,322, 3,725,072 and 3,891,445; West German Patent No. 1,547,868; and West German Patent (OLS) Publication Nos. 2,213,461, 2,219,917, 2,261,361, 2,414,006 and 2,263,875.
• magenta color developing couplers a pyrazolone type compound, an indazolone type compound and a cyanoacetyl compound can be used.
• the pyrazolone type compounds are particularly advantageous.
• the typical examples of the magenta color developing couplers applicable thereto include those given in U.S. Patent Nos. 2,600,788, 2,983,608, 3,062,653, 3,127,269, 3,314,476, 3,419,391, 3,519,429, 3,558,319, 3,582,322, 3,615,506, 3,834,908 and 3,891,445; West German Patent No. 1,810,464; West German Patent (OLS) Publication Nos. 2,468,865, 2,417,945, 2,418,959 and 2,424,467; and JP Examined Publication No. 40-6031/1965.
• a phenol type compound and a naphthol type compound can be used as for the cyan color developing couplers.
• the typical examples thereof include those given in U.S. Patent Nos. 2,369,929, 2,434,272, 2,474,293, 2,521,908, 2,895,826, 3,034,892, 3,311,476, 3,458,315, 3,476,563, 3,583,971, 3,591,383 and 3,767,411; West German Patent (OLS) Publication Nos. 2,414,830 and 2,454,329; and JP OPI Publication No. 48-59838/1973.
• DIR couplers As for the DIR couplers, it is allowed to use those given in, for example, U.S. Patent Nos. 3,227,554, 3,617,291, 3,701,783, 3,790,384 and 3,632,345; West German Patent (OLS) Publication Nos. 2,414,006, 2,454,301 and 2,454,329; British Patent No. 953,454; and JP Application No. 50-146570/1975.
• a light sensitive material is also allowed to contain, besides the above-mentioned DIR compounds, a compound capable of releasing a development inhibitor as a development is being progressed.
• the compounds applicable thereto include those given in, for example, U.S. Patent Nos. 3,297,445 and 3,379,529; and West German Patent (OLS) Publication No. 2,417,914.
• OPS West German Patent
• couplers may be contained in one and the same layer, independently or in combination, and one and the same compound may also be contained in two or more layers.
• the coupler is introduced into a silver halide emulsion layer in such a well-known method as mentioned in U.S. Patent No. 2,322,027.
• the coupler is dissolved in an alkyl phthalic acid ester (such as dibutyl phthalate and dioctyl phthalate), a phosphoric acid ester (such as diphenyl phosphate, triphenyl phosphate, tricresyl phosphate and dioctylbutyl phosphate) a citric acid ester (such as acetyltributyl citrate), a benzoic acid ester (such as octyl benzoate) and an alkylamide (such as dimethyllauryl amide) or an organic solvent having a boiling point within the range of about 30°C to 150°C including, for example, a lower alkyl acetate such as ethyl acetate and butyl acetate, ethyl propionate, secondary
• the coupler has an acid group such as those of carboxylic acid or sulfonic acid
• the coupler may be introduced in the form of an aqueous alkaline solution into a hydrophilic colloid.
• a silver halide emulsion layer may be added with these couplers in an amount within the range of, desirably, 2x10 ⁇ 3 mols to 5x10 ⁇ 1 mols and, preferably, 1x10 ⁇ 2 mols to 5x10 ⁇ 1 mols per mol of silver.
• a hydroquinone derivative and so forth may be used.
• the supports for forming a light sensitive material they include those made of baryta paper, polyethylene-coated paper, synthetic polypropylene paper, glass plate, cellulose acetate, cellulose nitrate, polyvinyl acetal and polypropylene, including, for example, a polyester film such as those made of polyethylene terephthalate, and a polystyrene film.
• the above-mentioned supports may be suitably selected so as to meet the application purposes of light sensitive materials and the support may be sublayered if required.
• the light sensitive materials used therein the emulsions of the invention can be fit for various uses including, for example, a variety of application such as general black-and-white photography, X-ray photography, color photography, infra-red photography, microphotography, a silver dye bleaching treatment, reversal photography and a diffusion transfer process.
• the speeds may also be improved by providing a reflective layer containing fine-grained silver halide grains underneath a high speed layer including particularly a high-speed blue sensitive layer.
• This technique is detailed in, for example, JP OPI Publication No. 59-160135/1984.
• the multilayered color photographic light sensitive materials containing the emulsions of the invention contain each a cyan forming coupler in the red-sensitive emulsion layer, a magenta forming coupler in the green-sensitive emulsion layer and a yellow forming coupler in the blue-sensitive emulsion layer thereof, respectively. It is allowed to have other different combinations if occasion demands. For example, it is also allowed to combine some infrared-sensitive layers for making a pseudocolor photography or a semiconductive laser exposure.
• the emulsions of the invention are useful for multilayered type color photographic light sensitive materials.
• the light sensitive materials of the invention generally have each ar least one of red-sensitive silver halide emulsion layers, one of green-sensitive silver halide emulsion layers and one of blue-sensitive silver halide emulsion layers. It is desirable that each of the same color-sensitive layers thereof is to have not less than two emulsion layers each having the different color-sensitivities. It is preferable that each of the layers is to have a three-layer structure and also that a method for improving the graininess is to be used.
• the above-mentioned techniques are described in, for example, British Patent No. 923,045 and JP Examined Publication No. 49-15495/1974.
• Solutions B and C of 9.08 ml each were added into Solution A at 35°C by making use of the mixing stirrer detailed in JP Examined Publication No. 58-58288/1983 and 58-58289/1983 in a double-jet precipitation method by taking 2 minutes, so that the nuclei were produced.
• Solution A was raised up to 60°C by taking 30 minutes and Solutions B and C were each added again in a flow rate of 19.5 ml/min. in a double-jet precipitation method by taking 25 minutes.
• the silver potential was controlled to be +6 mv with Solution D (wherein the silver potential was measured at the silver ion selection electrode while serving a saturated silver-silver chloride electrode as the reference electrode.)
• the pH was kept at 6 with a 3% KOH solution and an aqueous solution containing 21.3 g of ossein gelatin was added, so that seed emulsion EM-0 was prepared.
• the resulting seed emulsion EM-0 was proved to be the hexagonal tabular-shaped grains having the maximum adjacent side ratio within the range of 1.0 to 2.0 in not less than 90% of the whole projective area of the silver halide grains and also proved through an electron microscopic observation to be that the tabular-shaped grains had an average grain thickness of 0.07 ⁇ m and an average grain size (converted into an average circular diameter) of 0.5 ⁇ m. Seed grain EM-0 contained 0.6215 mols in 4612 ml thereof.
• a tabular-shaped silver iodobromide emulsion EM-1 containing 2.46 mol% of AgI was prepared by making use of 4 kinds of the following solutions.
• the silver potential was controlled to be +28.0 mV by making use of Solution D.
• a washing treatment was carried out in an ordinary manner in a precipitation method (in which phenyl carbamoyl type gelatin was used) so as to remove the excessive salts. After that, an aqueous gelatin solution containing 47.57 g of ossein gelatin was added thereto and was then so stirred as to be dispersed again.
• the resulting emulsion EM-1 contained 5.756 mols of silver halide in 2445 ml thereof and the pH and pAg thereof were controlled to be 5.8 and 8.06 at 40°C, respectively.
• the configurations of about 3000 grains of EM-1 were analyzed by observing and measuring them through an electron microscope. The results thereof are shown in Table-1.
• EM-1 the proportion of the grains having an aspect ratio within the range of 3.0 to 7.0 was proved to be 81.1%.
• 50% of the whole projective area of the silver halide grains was occupied by the grains having an aspect ratio of not less than 4.34, and 70% of the whole projective area thereof was occupied by the tabular-shaped grains having an aspect ratio of not less than 3.86.
• the whole silver halide grain projective area of 93%, that was not less than 90% thereof, were also proved to be occupied by the hexagonal tabular-shaped grains having a maximum adjacent side ratio within the range of 1.0 to 2.0.
• the average grain size was 0.92 ⁇ (converted into the average circle diameter thereof); the grain size distribution thereof was 21.8% in terms of the variation coefficient; the average grain thickness was 0.218 ⁇ m; and the thickness variation coefficient was 15%.
• Tabular-shaped silver iodobromide emulsion EM-2 of the invention containing 3.18 mol% of AgI was prepared by making use of the 4 kinds of the following solutions.
• the silver potential was controlled to be +38.0 mV by making use of Solution D.
• a washing treatment was carried out in an ordinary manner in a precipitation method (in which phenyl carbamoyl type gelatin was used) so as to remove the excessive salts. After that, an aqueous gelatin solution containing 29.3 g of ossein gelatin was added thereto and was then so stirred as to be dispersed again.
• the resulting EM-2 contained 4.94 mols of silver halide in 2660 ml thereof.
• the pH and pAg of the emulsion solution were controlled to be 5.8 and 8.06 at 40°C, respectively.
• the configurations of about 3000 grains of EM-2 were analyzed by observing and measuring them through an electron microscope. The results thereof are shown in Table-1.
• the proportion of the grains having an aspect ratio within the range of 3.0 to 7.0 was proved to be 76%.
• 50% of the whole projective area of the silver halide grains was occupied by the grains having an aspect ratio of not less than 4.07, and 70% of the whole projective area thereof was occupied by the tabular-shaped grains having an aspect ratio of not less than 3.33.
• the average grain size was 0.62 ⁇ (converted into the average circle diameter thereof); the grain size distribution thereof was 24.2% in terms of the variation coefficient; the average grain thickness was 0.163 ⁇ m; and the thickness variation coefficient was 9%.
• the emulsions EM-3 through EM-15 each having the different variation coefficients and aspect ratios were each prepared in the same manner as in the emulsion EM-1 prepared in Example-1.
• the variation coefficients and aspect ratios of these comparative emulsions were controlled by varying the amounts of the seed emulsion used and the silver potentials given in the course of the growing the seed emulsion EM-0.
• the silver potentials in the course of growing the seed emulsion were so controlled as to have the different values between the first half of the growth (to be in a 1/2 amount of silver added) and the last half thereof so as to meet the requirements.
• the optimum adding rates of Solution B and C were each selected (to be the critical growth rates) by adjusting the amount of the seed emulsion and the silver potential for the growth so as not to produce any new nucleus other than those of the seed emulsion, so that the growth was carried out.
• Table-2 shows the conditions for growing EM-3 through EM-15 and the configurational parameters of the silver halide grains contained each in the emulsions.
• Silver halide photographic light sensitive materials were prepared by chemically and spectrally sensitizing the emulsions EM-1 through EM-19 (to be blue- and green-sensitive) in the ordinary methods, respectively, and the effects of the emulsions of the invention were compared to each other.
• Multilayered color photographic light sensitive materials were prepared in quite the same conditions as in those given in JP Application No. 2-10971/1989, except that the other blue-sensitive emulsions were used therein.
• Samples No.1 through No.19 were each prepared by replacing the silver halide emulsions contained in the high-speed blue-sensitive layers and the low-speed blue-sensitive layers thereof by the same amounts of chemically sensitized emulsions EM-1 through EM-19.
• color photographic light sensitive materials can be so prepared as to have an excellent image-sharpness, to reduce the deterioration caused by a pressure desensitization and a pressure fog production and to have an excellent gradation.
• Sample No.20 was so prepared as to contain the emulsion of the invention, EM-2, in the low-speed blue-sensitive layer thereof.
• the same evaluations as in the above-mentioned were made on Sample No.20.
• the resulting Sample No.20 proves that the image-sharpness of the green-sensitive layers can be improved and that the image-sharpness of the green-sensitive layers can preferably be improved especially when making use of the emulsions of the invention in both of the high-speed and low-speed blue-sensitive layers thereof.
• the image-sharpness of the red-sensitive layers can desirably be improved similar to the above-mentioned case, when making use of the emulsions of the invention in the green-sensitive layers.

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• 1991
  • 1991-05-20 JP JP14389591A patent/JPH05173272A/ja active Pending
• 1992
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